Digital audio data may include a dialog normalization (dialnorm) metadata parameter to set a standard volume level for dialog encoded by the digital audio data. The purpose of the dialnorm parameter is to prevent major changes in perceived volume level when media content changes, such as when one television program ends and another television program begins. The dialnorm parameter may be used by devices, such as set-top box devices, that decode digital audio data to maintain dialog of different content at the same perceived volume level. For example, a set-top box device may modify the dialnorm metadata parameter to maintain a −20 decibels Full Scale (dbFS) dialog level. To illustrate, when the set-top box device receives a movie having a dialnorm of −25 dbFS, the set-top box device may increase the dialnorm by 5 db and output the movie at a −20 dbFS dialog level. When the set-top box device receives a television program having a dialnorm of −18 dbFS, the set-top box device may decrease the dialnorm by 2 db to a −20 dbFS dialog level. In this way, the movie and the television program are output with the same dialnorm in an attempt to minimize any perceived difference in volume when media content received by the set-top box device transitions from the movie to the television program.
However, advertisers may reduce the dynamic range of advertisements while keeping the dialnorm at the same value as media content, resulting in the advertisements having a greater perceived loudness than the media content. Some viewers may find the perceived fluctuation in loudness from the media content to the advertisement annoying.